Oil production and communication applications in subsea environments require electric devices able to withstand high pressure. However, electronic components, such as capacitors, particularly conventional electrolytic capacitors or MP capacitors are not applicable under high pressure conditions. Such capacitors exhibit electrodes stacked and rolled up in a casing partially filled with an electrolytic fluid, which would collapse under high pressure.
Electric devices containing such electronic components are often designed with a pressure proof housing in order to keep the interior of the housing at atmospheric pressure (1 atm). Due to the high pressure in deep sea environments (e.g. 300 bar at 3000 m depth) this housing needs to be adequately massive thus causing high costs.
Further drawbacks are the high effort for sealing the housing and the feedthroughs for electrical connections to the outside.
In other known approaches the housing of such electric devices is filled with an electrically insulating fluid. Although this allows a lightweight design of the device housing, the risk of damage to the capacitors persists because they are exposed to the ambient pressure transmitted by fluid in the device housing. Casting capacitors in a resin yields the risk of enclosing gas or air filled bubbles within the resin or in the capacitor itself which may cause problems when exposed to high pressure.